Control of railway trains



Oct. 9, 1928. 1,687,272

w. J. UNDERwooD A CONTROL OF RAILWAY TRAINS Filed June 5, 1926 4 Sheets-Sheet 1 Oct. 9, 1928.

W. J. UNDERWOOD CONTROL OF RAILWAY TRAINS Filed June 5, 1926 4 Sheets-Sheet Oct. 9, 1928.

1,687,272 W. J. UNDEIRWOOD CONTROL OF RAILWAY TRAINS Filed June 5. 1926 4 Sheets-Sheet 3 Oct. 9, 1928. 1,687,272

w. J. uNDERwooD CONTROL OF RAILWAY TRAINS :ill

Patented Oct. 9, 1928.

UNITED STATES PATENT OFFICE.

WALTER JOHN 'UNDERWOOD, 0F CHELSEA, LONDON, ENGLAND.

CONTROL F RAILWAY TRAINS.

Application led .Tune 5, 1926, Serial No. 113,947, and in Great Britain March 30, 1926.

This invention relates to the control of railway trains and consists in an improvement in the invention described in my Patent No. 1,497,416.

The improvement according to the present invention consists in the provision of one or more. additional contacts on the controlling switches described in the earlier speciication, and circuit connections to said contacts to enable the controlling switches, or any of them, to have one or more additional operative positions, or functions, or both, and thereby to effect various auxiliary purposes connected with or supplemental to the operation oi the train controlling apparatus.

In the following description and claims the movement of a controlling switch tor the purpose ot initiating the departure ot' a train from the corresponding station will be referred to as the initiating' movement and the position to which it is moved for that purpose the initiating position of the switch, and the opposite movement and position, for permitting' the approach of a train to the correspondinoV station, will be referred to as the permissive movement and position of the switch.

Examples according to the invention are illustrated in the accompanying drawings in which 1 is a diagram of the principal oper ative circuits for the control of 'trains on a single track railway, and includes an additional Contact on each controlling switch and connections thereto in accordance with the present invention;

Fig. 2 is a diagram similar to Fig. 1, and includes a second additional contact on each controlling switch and a modified circuit connected thereto in accordance with the present invention;

Fig. 8 is a modilication of part ot the diagram of Fig. 2;

Fig. 4 is a modification of the whole of Fic. 2.

Referring to Fig. 1 of the drawings, the arrangement shown herein is similar to thatshown in Fig'. 1 of my Patent No. 1,497,416, but only a sufficient number of parts are now shown to enable the present object in view and the manner in which it is carried out to be clearly understood.

Two stations A and B are shown connected to a section C of a single track railway, the said section comprising track rails 1 and 2 of indeinite length and electrically continuous throughout. The electrically continuous rail 1 is defined by the track insulation D and E at opposite ends of the same.

At station A the branch arrival track for trains travelling from left to right is shown at 3 consisting of rails 4 and 5, while that for trains travelling from right to left is shown at 6 consisting of rails 7 and 8. At station B the corresponding branch arrival tracks are shown at 9 consisting of rails 10 and 11, and at 12 consisting of rails 13 and 14.

In the arrangement according to the present invention shown in Fig. 1, the rail 2 of the single track section C is made electrically continuous, both with one rail 8 of the branch arrival track 6 at station A and also with one rail l0 of the branch arrival track 9 at station B, the inter-bonded rails 8, 2 and 10 being defined by track insulation D2 at station A and E2 at station B.

The technical object in view ist as stated above, to enable the controlling switches to be utilized Jfor various auxiliary purposes in addition to their main function disclosed in my carl ier Patent No. 1,497,416, and this object is achieved by providing said switches with additional contacts to which circuit conductors are connected according to the particular auxiliary purposes in view. In some cases, such for example as are illustrated in the accompanying drawings, the additional contacts are arranged so that the auxiliary circuit, or circuits, is or are, closed in one of the ordinary operative positions of the switch. ln other cases auxiliary circuits may be closed by lproviding additional positions for the switches.

An important auxiliary purpose which is provided for in each of the arrangements illustrated in the accompanying drawings is to prevent a train from leaving a station as long as another train travelling in the same direction is standing at the station in advence.

The extension of the electrical continuity oi the rails of the single track sections to the branch arrival tracks at the stations is not a practicable solution of the problem as` although this would certainly have the desired ei'ect as far as a following train is concerned, it would also render itl impossible for two trains to pass one another at the stations, as the train on one branch track at a station rIll could not be started by reason of the shortcircuiting action of the train on the other branch track at the same station.

The most important auxiliary purpose in view according to the present invention is to render it impossible to despatch a following train from a station as long as a preceding train is standing at the station in advance, without interfering with trains which are travelling in opposite directions passing one another at the stations. Other auxiliary purposes also may be provided for by means of additional contacts on the controlling switches, whether combined or not with the above mentioned auxiliary purpose.

Proceeding with the description of Fig. 1, at station A a controlling switch is pro` vided having a tendency, for example by means of the weight 16 on the larm 17, to re main in, and to return to when moved from, its neutral position in which all the circuits controlled by the switch are open. In this arrangement the switch has only two positions indicated by the dotted lines I and II, of which I is the initiating and II the permissive position.

In position I of switch 15 are arranged contacts 18, 19 and 20, of which contact 18 is connected by a wire 21 to one pole of battery 22, contact 19 is connected by a Wire 23 to rail 8, and contact is connected by a wire 24 to one end of a coil 25 controlling the departure of trains from station A towards station B, that is, from the branch track 3 on to the single track section C, the other end of the coil 25 being connected to the line wire 26.

In position II of switch 15 are arranged contacts 27, 28, 29, of which contact 27 is connected by a wire 30 to the other pole of battery 22, contact 28 is connected by a wire 3l to a length 32 of rail 7 which is insulated by means of track insulation F and G, while contact 29 is connected by a wire 33 to the line wire 26.

At station B a controlling switch 34 is provided similar to the switch 15 at station A, and having a weight 35 on the arm 36 tending to maintain the switch in its neutral position, or to return it thereto when moved from it. The circuits connected to switch 34 are similar to those connected to switch 15, but while switch 15 is for initiating the movement of trains from A to B and permissively controlling trains coming from B, switch 34 is for initiating the movement of trains from B towards A and permissively controlling the trains coming from A.

In position I of switch 34 are arranged contacts 37, 38 and 39, of which contact 37 is connected by a wire 40 to one pole of battery 41, contact 38 is connected by a wire 42 to rail 10, and contact 39 is connected by a wire 43 to one end of a coil 44 controlling the departure of trains from station B towards A, that is, from the branch track 12 on to the single aca/,eva

track section C, the other end of the coil 44 being connected to the line wire 26.

In position II ot switch 34 are arranged contacts 45, 46, and 47, oi"Y which contact 45 is connected by a wire 48 to the other pole of battery 41, contact 46 is connected by a wire 49 to a length 50 of rail 11 which is insulated by means of track insulation H and J, while contact 47 is connected by a wire 51 to the line wire 26.

The end of rail 1 adjacent to station A is connected to the return side oit' battery 22 by a wire 52, and the opposite end et' the rail adj acent to station B is connected to the return side of battery 41 by a wire 53.

On the lett at station A a portion o a wire 49 is shown connected to an insulated length ot rail 50 in rail 5. These parts correspond to the wire 49 and length of rail 50 at station B and operate in connection with the next single track section on the left of A. Similarly, on the right at station B a portion of a wire 31 is shown connected to an insulated length of rail in rail 13, these parts corresponding to the wire 3l and insulated. length of rail at station A, and operating in connection with the next single track section on the right ot' B.

Indicating ammetcrs 54 and 55 may be inserted in the connections 21 and 30 at A, and ammeters 56 and 57 be inserted in the corresponding connections 40 and 48 at B.

The above described arrangements and the operation of the system or" which they form a part are, in general, similar to the arrangements and the operation described in my earlier specification. The additional contacts and modiiied connections according to this invention comprise, at station A, the contact 28 in position II ot switch 15, and the wire 31 connecting the same to the insulated rail 32; at station B, the conta 46 in position Il oi switch 34 and the wire 49 connecting the same to the insulated rail 50; also the modifications in the track bonding and insuiation, consisting in makine one rait, Afor t rail 2, of the single` track section electrically continuous with a rail 8 at station A and withl a rail 10 at station B, combined with the provision of insulated rails 32 (at A) and 50 (at B).

In describing the operation it is necessary to suppose that to despatch a train from one station towards the next while a preceding train is standing at the arrival platform of said next station is contrary to the regulations governing the traiiic and that the two signalmen at A and B co-operate in an irregular attempt to despatch a train under the conditions named. If only one ot' the two signalmen turns his controlling switch into the ap iropriate position for carrying out the irregular train movement no circuit is closed and no eifect is produced.

The signalman at A, after communicating with B, attempts to start a train from the branch track 3 at A towards B while a preceding train is standing on the branch track 9 at B, and for this purpose moves his switch 15 into its initiating position I; the signalman at B, forgetful of the train on track 9, turns his switch 34 into its position II to cooperate permissively with A. This results in closing the circuit from battery 22 through wire 21 to contacts 18 and 20, thence by wire 24 to coil 25, through line wire 26, wire 51, contact 47 of switch 34 at B, thence to contact 45, through wires 48 and 53 to rail 1, and thence by wire 52 back to the return side of battery 22. Owing however to the train standing on track 9 connecting the rail 10 to the insulated length of rail 50 as shown by the dotted line, a shunt to coil 25 is also closed from the battery 22 through wire 21 and contact 18 to contact 19 at switch 15, thence through wire 23, rail 2, rail 10, rail length 50, thence through wire 49, contact 4G at switch 34, to contact 45, through wire 48, wire 53 to rail 1, and thence through wire 52 back to the return side of battery This short-circuits the coil 25 and prevents it from receiving an operative current. A short-circuit current will iow through ammeter 54 at A and ammeter 57 at B and these instruments will warn the two signalmen that something is wrong.

When the train has left branch track 9 at B the same movement of the switches 15 and 34 will cause coil 25 to be energized and enable a train to pass from station A to B in the normal manner.

Fig. 2 shows the combination of an arrangement of the kind shown in Fig. 1 with an arrangement designed to carry out a second auxiliary purpose by means of a Second additional contact on the controlling switches, and circuit connections therewith. The auxiliary purpose underlying this arrangen'ient is to materially reduce the shortcircuiting of the batteries and the wastage of current thereby in the automatic safety operation of the system.

For this purpose the additional contact 58 is provided at switch 15 and arranged so as to be engaged by the switch in its permissive position. the said contact 58 being connected to the rail 1 by a wire 59. A contact G0 is similarly arranged on switch 34 and is connected to rail 1 by a wire 61. lVith this arrangement the negative poles of the batteries 22 and 41 are connected by a second line wire (52, or by carthing the said poles as shown in dotted lines at G3 and 64.

To explain the operation it will be supposed that a train is on the single track section C and the signalman at A inadvertently attempts to start a train from A towards B by turning his switch 15 into position I. Such an action would short-circuit the battery 22 with an arrangement of the kind shown in my earlier Patent No. 1,497,416 and also with that shown in the present Fig. 1. But with the additional contacts and connections according to Fig. 2 a shortcircuit on either of the batteries 22 or 41 can only be closed by both signalmen at A and B attempting to co-operate to start the train under danger conditions. If only one signalman alone moves his switch an operative circuit cannot be closed in any case and it is therefore unnecessary, for the purpose of safety, that the irregular action of one signalman alone should cause a short circuit.

Referring to Fig. 2, it will be seen that the movement of switch 15 into position I while a train is on section C fails to short-circuit battery 22 because the wire 59 is not directly connected to the battery. If however the switch 34 at B is simultaneously moved to its position II, then a circuit is completed from battery 22 through wire 21, contacts 18 and 19, wire 23 to rail 2, thence through the wheels and axles of the train to rail 1, thence through wire 61 to additional Contact 60, through switch 34, Contact 45, wire 48 and second line wire 62, or earth 64, back to the battery 22.

The remaining parts shown in Fig. 2 are the same as the similarly numbered parts in F ig. 1, with the exceptions that the wires 52 and 53 of Fig. 1 are replaced by the wires 59 and G1 of Fig. 2. It will be understood that the arrangement for reducing the short circuiting of the batteries in the normal operation of the system may be used alone, if desired, without being combined with an arrangement of the kind shown in Fig. 1.

Fig. 3 shows a simplified arrangement for reducing the short-circuiting of the batteries, this arrangement being a modilication of that part of Fig. 2 relating to this subject. In this case the track insulation D', D2 is shown arranged at the left-hand end and E E2 at the right-hand end of the single track section, while the remaining parts are given the same reference numerals as in Figs. l and 2 so far as the parts are the same as in these figures. In the moditied arrangement however shown in Fig. 3 the short circuit contacts 19 and 38 on the initiating sides of the switches 15 and 34 respectively are connected to opposite rails ot' the single track section instead of being connected to the same rail as in Figs. 1 and 2 and as described in the said earlier specification. Thus the wire 23 is sho-wn connecting contact 19 to rail 2 and the wire 42 connecting contact 38 to rail 1. Also, the short-circuit contacts 28 and 46 on the permissive sides of the switches 15 and 34 are directly connected by wires 65 and 66 to the said wires 23 and 42 respectively. Alternatively, each pair of short-circuiting contacts, namely, 19, 28 of switch 15, and 38, 46 of switch 34, may be directly connected with one another by a strip or the like of metal, giving the same eiect as the connections 65, 66.

To explain the operation, it will be supposed that the switch 15 at A is moved into its posit-ion 1 to initiate the movement of a train from A towards B, and the switch 34 at B is at the same time moved into its position II to permit the said movement while a train is on the single track section. This results in a short circuit starting from battery 22. through wire 21, contacts 18 and 19 connected by switch 15, through wir to rail thence through the wheels and axles of the train to rail 1, through wires 42 and 6G to contacts 46 and 45 connected by switch 34, wire 48, and earths 64 and 63 back to battery 22. This short circuit is only completed if both signalmen co-operate in attempting to bring about the irregular movement. It the single track section is unoccupied by a train the coil 25 would be energized by the said movements ot' the two switches 15 and 34, to allow the train at A to pass on to the single track section in the normal manner.

The practical value ot the earth connections shown in Fig. 3 will of course depend upon the extent to which leakage from the rails 1 and to earth can be suliiciently reduced. lVhen this leakage is considemble it mightbe impossible to operate the system with the earth connections owing to the coils 25 and 44 being shunted b v the leakage circuit through earth. This question ot leakage however can be entirely eliminated by en'iploying the additional line wire 62 instead of the earth connections. By this arrangement the short-circuiting of the batteries can be rendered quite exceptional by reason of it being necessary for two operators (after communieating with one another) to act wrongly at the same time in order to make a short-circuit, instead ot only one operator alone as in the arrangement described in the earlier Patent No. 1.497,416. This result may well be considered worth obtaining in certain cases, even if a second line wire for each section is necessary for this purpose.

Fig. 4 is a modification of the arrangement shown in Fig. 2 based upon the arrangement shown in Fig. 3, that is to say, Fig. 4 combines an arrangement for preventing the despatch of a following train from a station while a preceding' train is standing at the station in advance, with an arrangement of the kind shown in Fig. 3 for reducing the short-cireuiting of the batteries in the normal working of the system. Those parts in Fig. 4 which have been shown in any of the previously described iigures are given the same reference numerals as before.

Referring to Fig. 4 the rail 2 is made electrically continuous at one end with the rail 10 of the branch arrival track 9 at station B, the bonded part of rail 10 terminating at the track insulation E2, While the other end of rail 2 terminates at the commencement of the single track section C and is defined by the track insulation D2. Similarly, one end of rail 1 is detined by the track insulation E arranged at the end ot the single track section opposite to the end defined by the track insulation D2 in rail 2, while the other end et rail l is made electrically continuous with the rail 7 the bonded part oi' which terminates at the track insulation D.

At station B the insulated rail 50 is arranged as before in rail 11 of arrival track 9, but at station A the insulated rail 32 is arranged in rail 3 of arrival track 6 instead of in rail 7 as shown in Figs. 1 and 2. Instead of connecting the insulated rails 32 and 50 by wires 31 and 49 to contacts 28 and 46 respectively. in Figs. 1 and 2. the rail 32 is connected by wire 31 to an additional contact 67 provided on switch 15, and the rail 5() is connected by wire 49 to an additional contact 68 provided on switch 34. The switch 15 is provided with a contact piece 69 adapted to bridge the contacts 29 and 67 and to enable all tour contacts 27, 28, 29, 67 to be connected together and to earth 63 (or line Wire 62) in the permissive position ot' the switch. Similarly the switch 34 is provided with a contact piece 70 bridging the contacts 47 and 68 and enabling all four contacts 45. 46, 47 and 68 to be connected together and to earth 6 4 (or line wire 62) in the permissive position.

In all the arrangements,described, when a controlling switch 15 or 34 is in its neutral position, all the controlling circuits governed by the switch should be open and each circuit disconnected from all other circuits.

Vilhat I claim and desire to secure by Letters Patent is 1. For electrically controlling the trailic on a single track railway section, the combination with electrically continuous track rails ot the section and a station at each end oi the same. ot a line conductor extending between the two stations, a traflic-controlling device and a source ot current at each station, two alternative operating circuits, one including the trafiic-controlling device and the source ot current at one station. the other including` the trame-controlling device and the source ot current at the other station, but each circuit including the line conductor, a controlling switch at each station having a normally neutral position, contacts on the switches and connections thereto enabling the switches to close` one only of the operating circuits at a time to move a train trom one station on to the section, an additional circuit auxiliary to the operating circuit, and an additional contact on each controlling switch for closing the said auxiliary circuit by the simultaneous movement of both switches from their neutral positions.

2. Apparatus according to claim 1, comhis prising an additional contact on the pcrmissive side of a controlling switch, one rail of the arrival track at a station being made electrically continuous up to a sufficiently advanced point with the corresponding rail otl the section, an insulated length of track rail in the opposite rail of the said arrival track, and a connection therefrom to said additional contact on the controlling switch.

3. Apparatus according to claim l, coniprising an additional Contact on the permissive side ot each controlling switch, a connection from each said contact to a rail ol the section, a contact on the initiating side of each controlling switch. a connection from each said contact the other rail ot the section, and a direct connection, other 'than through a rail of the section, between the return side ot the source of currrnt at one station with that of the source ot current at the other station, to cause the source ot current at the initiating station to be short-circuited only itl and when the operators at both stations attempt. to co-operate to move a train from the initiating station on to the section under danger conditions.

4. Apparatus according to claim l, coinprising a further additional contact on the permissive sidel ot each controlling switch, one rail 0f the arrival track at each station being made electrically continuous up to a. sufliciently advanced point with the corresponding rail of the section, an insulated length of track rail in the opposite rail of said arrival track, a connection therefrom to one ot said additional contacts on the corresponding controlling switch, and a connection from the second additional Contact on the switch to the rail of the section which is electrically discontinuous with the corresponding rail ot' the arrival track.

5. Apparatus according to claim l comprising an additional contact on the permissive side ot' each controlling switch, a connection from the additional contact of one controlling switch to one rail of the section, a connection tro-1n the additional contact ot they other controlling switch to the other rail ot the section, a contact on the initiating side ot each controlling switch, a connection therefrom to the additional contact on the permissive side of the switch, and a direct connection, other than through a rail of a section, between the return side ot the source ot' current at one station and that of the source ot current at the other station.

ln testimony whereof I have signed my naine to this specification.

WALTER JOHN UNDERWOOD. 

